Determination of the chemical states of sulfur in ambient pollution aerosols by X-ray photoelectron spectroscopy

Abstract

The chemical states of sulfur present in ambient paniculate matter have been identified by use of X-ray photoelectron spectroscopy (X.P.S.-E.S.C.A.) Seven separate chemical species of sulfur were found in atmospheric samples taken in California. These, in terms of net sulfur charge, are SO 3.SO 4 2−, SO 2. SO 3 2−, S 0 and two kinds of sulfides. Sulfates were found to be the dominant species, although reduced forms of sulfur were at times comparable to the sulfate concentrations.